The combined oral contraceptive pill (COCP), often referred to as the birth-control pill or simply "the Pill", is a birth control method that includes a combination of an estrogen and a progestin. When taken by mouth every day, these pills inhibit female fertility. They were first approved for contraceptive use in the United States in 1960, and are a very popular form of birth control. They are currently used by more than 100 million women worldwide and by almost 12 million women in the United States. Usage varies widely by country, age, education, and marital status: one third of women aged 16–49 in Great Britain currently use either the combined pill or a progestogen-only "minipill", compared to only 1% of women in Japan.